南方医科大学学报

南方医科大学学报 ›› 2021, Vol. 41 ›› Issue (8): 1191-1197.doi: 10.12122/j.issn.1673-4254.2021.08.10

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体育锻炼与缺血性卒中复发风险存在因果关系：基于潜在结果理论

林奕蝶，张柏杨，胡美婧，徐铭涵，秦成洁，朱彩蓉   

  1. 四川大学华西公共卫生学院//四川大学华西第四医院流行病与卫生统计学系，四川 成都 610041
  • 出版日期:2021-08-20 发布日期:2021-09-07

Causal relationship between physical exercise and risk of ischemic stroke recurrence based on the potential outcome theory

LIN Yidie, ZHANG Baiyang, HU Meijing, XU Minghan, QIN Chengjie, ZHU Cairong   

  1. Department of Epidemiology and Health Statistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu 610041, China
  • Online:2021-08-20 Published:2021-09-07

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摘要： 目的 基于潜在结果理论，采用多重插补法探讨体育锻炼与缺血性卒中复发风险之间的因果关系。方法 收集2010年7月 ~2018年12月入住四川大学华西医院、随访时间满1年且具有行动能力的首发缺血性脑卒中幸存者生存资料。共纳入636例首发缺血性脑卒中患者，将观察对象分为两组：低体育锻炼水平组（LPE）244人，中高体育锻炼水平组（MHPE）392人。采用潜在结果理论将是否复发和复发时间作为每个观察对象在不同体育锻炼水平下的潜在结果，由于实际只能观察到每个个体在一种暴露水平下的潜在结果，因此在个体反事实的潜在结果必然缺失的条件下，采用多重插补法建立缺失结果的预测矩阵并进行填补，构建因果推断模型，估计体育锻炼对卒中复发的平均因果效应。结果 随访期间共148名患者卒中复发，中位复发时间为24个月，累计复发率高达23.3%。对比多重插补前后数据集的分类散点图及核密度图，多重插补的结果没有出现异常点，潜在结果变量的边际分布较为一致，插补效果稳定。基于插补后的10个完整数据集构建因果估计模型并对所得结果进行合并，得到体育锻炼对卒中复发的平均因果效应为ACE=0.578，方差为0.039，即中高体育锻炼水平的首发缺血性卒中幸存者的复发风险是低体育锻炼水平者的0.578倍（95% CI：0.186-0.970，P=0.012）。结论 体育锻炼与缺血性卒中复发风险之间存在因果关系，即卒中后参与中高强度水平的体育锻炼可以降低卒中复发的风险。

关键词: 体育锻炼；缺血性卒中；潜在结果；多重插补法；因果推断

Abstract: Objective To explore the causal relationship between physical exercise and ischemic stroke recurrence using a multiple imputation approach based on the potential outcomes framework. Methods We collected data from 636 patients who were diagnosed with first-ever ischemic stroke between July, 2010 and December, 2018 at West China Hospital, Sichuan University. All the patients had motor ability and were followed up at least for 1 year. According to the intensity of physical exercise, the patients were divided into low-level physical exercise (LPE) group (n=244) and moderate-to high-intensity exercise (MHPE) group (n=392). With both the result and the time of recurrence as the potential outcomes, a multiple imputation method was used to impute the missing values based on a predictive matrix. Based on the imputed datasets, a causal inference model was built to estimate the average causal effect of physical exercise on the risk of stroke recurrence. Results Among the enrolled patients, 148 experienced recurrent stroke with a median recurrence time of 24.0 months and a cumulative recurrence rate of 23.3% during follow-up. As there were no outliers and the marginal distributions of the potential outcomes were basically consistent, both the Strip plots and Kenel density plots indicated that the imputed values could have been plausible measurements if they had not been missing. The average causal effect (ACE) of physical exercise on stroke recurrence was 0.578 (95% CI: 0.186-0.970, P=0.012). Conclusion There is a causal relationship between physical exercise and the risk of ischemic stroke recurrence, indicating the value of moderate or high-level exercise after stroke in reducing the risk of stroke recurrence.

Key words: physical exercise; ischemic stroke; potential outcome; multiple imputation; causal inference